Copper and its alloys should not be used where they can come into contact with ammonium nitrate. The presence of copper represents the single greatest hazard with respect to the accidental detonation of ammonium nitrate during a fire.
Steel and wood can be protected with special coatings such as sodium silicate, epoxy, or polyvinyl chloride.
Asphalt and similar hydrocarbon-based roof coverings should not be used. Stored ammonium nitrate may become sensitized during a fire if such roof coverings melt and leak into the interior of the building, causing burning droplets to fall on the stored product.